The invention is directed to an electrical assembly with an electrical or electronic component or part that generates noise signals with a disturbing frequency.
Diagnostic magnetic resonance apparatus work with high-frequency electromagnetic fields in the megahertz range. Two things occur. First, the magnetic resonance apparatus for exciting the nuclear magnetic resonance in an examination region of a patient emits high-power high-frequency pulses that can disturb the function of neighboring devices and equipment. Second, the magnetic resonance apparatus must receive and evaluate extremely low-power magnetic resonance signals that are emitted from the examination region. The magnetic resonance apparatus is, therefore, surrounded by an electro-magnetic shielding chamber to prevent disturbing interactions between the magnetic resonance apparatus and other electrical and electronic equipment.
It is often desirable to use other electrical or electronic devices in the shielding chamber in the immediate proximity of the magnetic resonance apparatus. For example, for interventional techniques in an open magnetic resonance apparatus, a further console for the input of commands with a monitor is required in the immediate proximity of the magnetic resonance apparatus. Noise emission from components with noise parts on the magnetic resonant frequency are problematical given such an arrangement since they can lead to the presence of artifacts in the magnetic resonance image. When an LCD module (liquid crystal display module) is utilized as a monitor, line switching with a basic frequency of, for example, 64 kHz also generates harmonics in the range of the magnetic resonance frequency.